
function beforeEach (fn) {
  global.beforeEach(function () {
    const result = fn();
    if (result instanceof Promise) {
      waitsForPromise(() => result);
    }
  });
}

function afterEach (fn) {
  global.afterEach(function () {
    const result = fn();
    if (result instanceof Promise) {
      waitsForPromise(() => result);
    }
  });
}

['it', 'fit', 'ffit', 'fffit'].forEach(function (name) {
  module.exports[name] = function (description, fn) {
    if (fn === undefined) {
      global[name](description);
      return;
    }

    global[name](description, function () {
      const result = fn();
      if (result instanceof Promise) {
        waitsForPromise(() => result);
      }
    });
  };
});

async function conditionPromise (condition, description = 'anonymous condition') {
  const startTime = Date.now();

  while (true) {
    await timeoutPromise(100);

    if (await condition()) {
      return;
    }

    if (Date.now() - startTime > 5000) {
      throw new Error('Timed out waiting on ' + description);
    }
  }
}

function timeoutPromise (timeout) {
  return new Promise(function (resolve) {
    global.setTimeout(resolve, timeout);
  });
}

function waitsForPromise (fn) {
  const promise = fn();
  global.waitsFor('spec promise to resolve', function (done) {
    promise.then(done, function (error) {
      jasmine.getEnv().currentSpec.fail(error);
      done();
    });
  });
}

function emitterEventPromise (emitter, event, timeout = 15000) {
  return new Promise((resolve, reject) => {
    const timeoutHandle = setTimeout(() => {
      reject(new Error(`Timed out waiting for '${event}' event`));
    }, timeout);
    emitter.once(event, () => {
      clearTimeout(timeoutHandle);
      resolve();
    });
  });
}

function promisify (original) {
  return function (...args) {
    return new Promise((resolve, reject) => {
      args.push((err, ...results) => {
        if (err) {
          reject(err);
        } else {
          resolve(...results);
        }
      });

      return original(...args);
    });
  };
}

function promisifySome (obj, fnNames) {
  const result = {};
  for (const fnName of fnNames) {
    result[fnName] = promisify(obj[fnName]);
  }
  return result;
}

module.exports = {
  promisify,
  promisifySome,
  emitterEventPromise,
  conditionPromise,
  timeoutPromise,
  beforeEach,
  afterEach
};
